1. Field of the Invention
The present invention relates to a liquid electrophotographic printer, and more particularly, to a photoreceptor belt cleaning apparatus for removing residual developer liquid and foreign matter remaining on a photoreceptor belt which is used as a photoreceptor medium.
2. Description of the Related Art
In general, in an electrophotographic printer, an electrostatic latent image formed on a photoreceptor medium such as a photoreceptor drum or a photoreceptor belt is developed using developer liquid having a toner mixed with a volatile liquid carrier and transferred to a sheet, thereby printing a desired image.
Referring to FIG. 1 schematically showing a conventional liquid electrophotographic color printer, a photoreceptor belt 110 circulates about a plurality of rollers 121, 122 and 123 which support the photoreceptor belt 110. The surface of the photoreceptor belt 110 is charged to a predetermined level by a charging station 150. Then, an electrostatic latent image is formed in the photoreceptor belt 110 by a laser scanning unit 130 for irradiating a laser beam onto the photoreceptor belt 11 according to image signals. The electrostatic latent image is developed by a development station 140 for supplying developer liquid. As shown in FIG. 1, in the case of a color printer, a plurality of laser scanning units 130 and a plurality of development stations 140 corresponding to various colors are provided.
As shown in FIG. 2, each of the development stations 140 includes a development roller 141, a cleaning roller 142 and squeegee rollers 144 and 146 directly under the photoreceptor belt 110. Additionally, the development stations each contains a developer liquid 148 in which a toner having a predetermined color and a liquid carrier are mixed. Reference numeral 143 represents a developer liquid supplier for supplying the developer liquid 148 between the development roller 141 and the photoreceptor belt 110.
The squeegee rollers 144 and 146 remove the residual developer liquid 148 after the developer liquid 148 is utilized for developing the electrostatic latent image. The removed developer liquid is withdrawn into the development station 140 by blades 145 and 147.
The liquid carrier contained in the developer liquid 148 sticking to the electrostatic latent image of the photoreceptor belt 110 is evaporated while passing the image drying station 160 so that only the toner remains on the photoreceptor belt 110 thereby completing the process for producing a developed image 148D.
Subsequently, the developed image 148D is transferred to a sheet 126 which is fed between a transfer roller 124 and a fixing roller 125 via the transfer roller 124, to then be printed. Thereafter, an electrostatic charge remaining in the photoreceptor belt 110 is removed by an erasure station 170.
Here, after the developed image 148D of the photoreceptor belt 110 is transferred to the sheet 126, the toner must be completely removed from the photoreceptor belt 110. However, if the developed image 148D is not completely transferred to the transfer roller 124, some toner sludge may remain on the photoreceptor belt 110. Also, foreign matter in the printer may stick to the photoreceptor belt 110 while the photoreceptor belt 110 circulates. The residual toner or foreign matter sticking to the photoreceptor belt 110 causes poor quality development in repetitive printing procedures, thereby adversely affecting the printing quality of a printed image.